In a semiconductor device manufacturing process, a batch-type heat treatment system has been used to collectively perform, for example, a film formation processing, an oxidation processing, and a diffusion processing on a plurality of workpieces such as, for example, semiconductor wafers. In the batch type heat treatment system, the semiconductor wafers may be efficiently processed. However, it is difficult to ensure uniformity of the heat treatment of the plurality of semiconductor wafers.
In order to solve the problem, for example, Japanese Patent Laid-Open Publication No. 11-121389 has proposed a method of providing three or more gas injectors for an upper portion, a central portion, and a lower portion to introduce a gas into a diffusion furnace and independently controlling the flow rates thereof to make the supply amount of the gas uniform, thereby enhancing the yield of semiconductor devices.
Further, Japanese Patent Laid Open Publication No. 2013-207109 has proposed a method of adjusting the heat treatment to satisfy a target heat treatment characteristic by calculating and controlling a temperature in a reaction chamber and a gas flow rate based on a heat treatment characteristic of a formed thin film, and a model representing a relationship between a change of the temperature in the reaction chamber and the gas flow rate and a change of the heat treatment characteristic.
Japanese Patent Laid Open Publication No. 2013-207110 has proposed a method of forming a laminated film of a target film thickness by calculating weighted values of respective layers from input target film thicknesses of a first and second films, calculating activation energy of a laminated film based on the calculated weighted values and activation energy, preparing a model of the laminated film based on a relationship between the calculated activation energy and a temperature in each zone in the film thicknesses of the first and second films, and calculating and controlling the optimal temperature for each zone using the prepared model of the laminated film.